1. Field of the Invention
This invention relates to an image processing method wherein an optimum image processing is performed automatically on photograph image data such as digital photograph image, and the image is evaluated, to an image processing apparatus, a medium on which an image processing control program is recorded, an image evaluation device, an image evaluation method, and a medium on which an image evaluation program is recorded.
2. Description of the Prior Art
Various kinds of image processing may be performed on digital image data, i.e., in which processing: contrast may be increased; color may be corrected; or lightness may be corrected. This image processing can usually be performed with a microcomputer. An operator confirms the image on a monitor, the necessary image processing is selected, and image processing parameters are determined.
In recent years various types of image processing techniques have been proposed, and are now having considerable impact. However, a human operator is still required when it is a question at which technique to apply, and to what extant it should be used. This is because it was otherwise impossible to determine which digital image data had to be subjected to image processing. For example, in the case of image processing to correct the lightness of an image, the screen is made lighter if it is dark on the whole, and is made darken if it is too light.
Now, consider the case of a photographic image of a person filmed at night, where the background is near to pitch-darkness but the person in the picture has been well photographed. If this photograph is automatically corrected, it is attempted to make the image brighter due to the fact that the background is pitch black, so the final image appears as if the photo was taken in the daytime.
In this case, if a human operator is involved, he pays attention only to the person in the picture. If the image of the person is dark, it would be made a little brighter, conversely darkening would be selected if the effect of flash, etc., was too bright.
Hence, there was a problem in the prior art in that a human operator had to participate to determine the important part (referred to hereafter as the “object”) of a photographic image.
However, even when the importance of the image is evaluated by some technique, the determination process is performed in picture element units, and varying the importance in real time causes an increase in computation.